No meat - Low carb, low fat, HIGH protein

You'll find some inspiration here:

https://community.myfitnesspal.com/en/discussion/10247171/carbs-and-fats-are-cheap-heres-a-guide-to-getting-your-proteins-worth-fiber-also#latest

My favorites are skyr yoghurt and chick peas.

Read the link Lietchi gave you.

Another plant-based option is seitan, but if you're avoiding gluten, don't bother. Can you eat eggs?

If you're looking for vegetarian options that are low in carbs and fat, but high protein, that's a hard-ish thing, beyond lowfat/nonfat dairy. Those 3 are the only macros, right, so if you rule out fat and carbs, you're looking for near-pure protein. Many plant sources of protein, such as legumes, come with at least some carbs.

Depending on your actual carb goals, subbing higher protein/lower carb options may help bump total protein upward (example: quinoa instead of rice, chickpea pasta instead of wheat pasta, etc.). If you're trying to be purely low(-ish) carb overall, that's tougher, realistically.

On the vegetable side, there are other things besides spinach that are a bit higher in protein (broccoli comes to mind), but those *tend* to be lower quality proteins (in terms of essential amino acid (EAA) profile).

I'm hitting 100g+ protein daily as an ovo-lacto vegetarian (5'5", 125-ish pounds, F) on maintenance calories (it was 80s-90s while at a deficit, typically), and I rarely eat eggs. (I never eat protein powder or bars, but only because I don't find them tasty/satisfying. They're also an option. Some vegetarian faux meats are OK on the protein/calorie ratio, but they do tend to be more expensive sources.)

How much protein are you targeting? Sometimes people aim higher than they need to. This is a research-based, generally considered unbiased source:

https://examine.com/nutrition/protein-intake-calculator/
https://examine.com/guides/protein-intake/

Eat fish.